Well I thought the same as many of the above comments, I’d grab the bike & call police.
However I’m generally not a confrontation type of person, so didn’t quite go like that at the time, think I was just generally surprised by it all.
Anyway stopped him for a “chat” some bull story of brother mates friend etc etc… his in good faith, don’t know what you’re talking about blah blah. Only a cheapish bike so without wanting to escalate with a potential minor, told him it’s nicked, obviously refused to give me any details, so told him fine I’ll take your picture. Took his photo and off he went… was all a bit weird.
Headed over to the police station with said photo, which caused some general confusion with the police staff as unusual apparently, but bike was recovered a couple of hours later by the police, after circulating photo and doing some policing, so big thumbs up there!. Picked it backup this morning.
Oh and no insurance claim, as we didn’t have away from home cover (at the time)